How to perfect patrolling Ai unity 3D?

void Update() { Ray ray = new Ray (transform.position, -transform.up); RaycastHit hitinfo; Physics.Raycast(ColDetect.position,dir, distance);

     if (Physics.Raycast (ray, out hitinfo))
     {
         if (hitinfo.collider.CompareTag("obstacle"))
         {
             touchground = true;
             print("true");
             transform.Rotate (0,0,0);
         }
         if (!hitinfo.collider.CompareTag("obstacle"))
         {
             touchground = false;
             print("false");
             transform.Rotate (0,180,0);
         }
     }

     if (touchground == true)
     {
       transform.Translate(Vector3.right * speed * Time.deltaTime);
     }
 }